Nathan Wheatear knows what kind of a boy he would like to be. He would like the chance to go to school and have friends. He doesn't want to be an apprentice rat catcher, nor kidnap children off the streets to sell to the orphanage for sweatshop labour, nor catch dogs and cats to sell for meat to the local pie shop, nor burgle the houses of the wealthy. But his dreadful uncle, Jago Blint, has plans for him. This man is a villain. You can tell that just from looking at his hat:

A dusty, shapeless stovepipe worn at a brash angle - similar to a thousand others, except in one respect: Jago was in the habit of hanging three or four freshly killed mice from the brim of his. Strung up by their tails, the mice swayed together in a kind of miniature gallows dance which so bewitched Nathan that he was unable to take his eyes off them.

This book tells the story of how Nathan manages to escape the clutches of his uncle and carve out an honest life for himself, simply by always doing what he believes to be right - or at least, behaving as well as he can despite his impossible circumstances.

Having rescued a boy from capture by Blint, Nathan and his new friend, Sam Hilliam, agree to swap identities. Sam, (the real Sam), means to run away with the circus and he gives Nathan his third class rail ticket to a third class school. Nathan is delighted at the prospect of furthering his education, but astonished by what he finds at Moonville School:

By the end of his first day, Nathan no longer felt quite so guilty for having taken on Sam Hilliam's identity. It was hardly fraud, he reasoned, when the school was just as big a fake as he was, for in all his time there he never once glimpsed a book or wetted a nib with ink. Smoking, wrestling, and frogs appeared to be the boys' main subjects and were taken up with a passion rarely associated with arithmetic and geography.

I'm not sure what kind of an education Nathan would have come away with if it hadn't been for the mysterious Mr Gentleman who quietly inhabits the Tower at Moonville. Mr Gentleman lends Nathan books from his own enormous library and so trust and friendship flourishes between them. In due course, Mr Gentleman has to go away on business but leaves Nathan in charge of his scientific researches back at home in the Tower.

So this is a bad moment for the awful Jago Blint to reappear. Falling once again under the crushing influence of Blint, Nathan is in danger of losing all he has worked so hard to achieve. You will have to read on, to see how he deals with the situation. Naturally, it will involve a borrowed pen knife, a gas-filled balloon, and an elephant named Cassia, lots of poetic justice and a happy ending.